1. Technical Field
The present invention relates to an image process of determining a dot formed state at the time of printing an image constructed with a plurality of pixels by using dots having a plurality of sizes.
2. Related Art
An ink jet printer is known as a printing apparatus that prints an image by forming dots on various printing media such as paper, a cloth, and a film. The ink jet printer prints the image on the printing medium by forming the ink dots on the printing medium by ejecting inks of colors, for example, cyan (C), magenta (M), yellow (Y), and black (K). In addition, there is an ink jet printer that can form dots having a plurality of sizes, for example, large dots (L dot), medium dots (M dots), and small dots (S dots).
In general, at the time of printing the image by using the ink jet printer, a process of determining the dot formed state of each of the printing pixels (referred to as a halftone process) is performed based on image data representing the image (refer to, for example, JP-A-2007-118238). Herein, the phrase “determining the dot formed state of each of the printing pixels” denotes determining which size and which color of the dot is formed at each of the printing pixels or determining whether no dot is formed.
In some cases, in the halftone process, there may be a limitation in a total amount of ink per unit area of the printing medium in order to suppress the occurrence of color bleeding. In this case, at the printing pixels constituting the edge portion of, for example, a character or a line drawing in the image, the dots having different sizes may be mixed, or no dot may be formed at some of the printing pixels. Therefore, due to the blurring or voids of the edge, the printing quality may deteriorate.
In addition, these problems are not limited to the printing of the image by the ink jet printer. Theses problems commonly occur at the time of determining the dot formed states of the printing pixels in the printing of the image by using the dots.